Experimental and theoretical analysis on the long-term performance of novel carbon fibre-reinforced polymer tendon composite anchorage

Carbon fibre-reinforced polymer (CFRP) has the advantages of light weight, high strength and superior corrosion resistance. In this study, the long-term performance of novel CFRP tendon composite anchorages was assessed, and the influences of the number of tendons, load level and over-tensioning was analysed. Then, the residual anchoring capacity of the anchorage after long-term performance test was determined. Finally, the slippage of CFRP tendons and the load loss were analysed based on the time strengthening theory. Results revealed that the composite anchorage had excellent long-term performance, and the six groups of specimens were intact after a long-term experiment. Over-tensioning significantly improved the long-term performance of specimens by reducing the load loss caused by the tendon slippage and the slippage of each measuring point. Furthermore, results of the long-term experiment showed that the residual anchoring efficiency of the remaining specimens was greater than 0.95, except for one group of specimens, because of incomplete axial tension. Eventually, the theoretical analysis results showed that over-tensioning can effectively reduce the load loss caused by the creep effect of the free section tendon. In summary, the novel composite anchorage displayed excellent reliability. This study provides a research case for the long-term performance of CFRP tendon anchorage and a basis for the application of the novel composite anchorage in practical engineering.